1 // SPDX-License-Identifier: (GPL-2.0 OR BSD-3-Clause)
2 //
3 // Copyright (c) 2018 Mellanox Technologies. All rights reserved.
4 // Copyright (c) 2018 Vadim Pasternak <vadimp@mellanox.com>
5 
6 #include <linux/bitops.h>
7 #include <linux/device.h>
8 #include <linux/hwmon.h>
9 #include <linux/module.h>
10 #include <linux/platform_data/mlxreg.h>
11 #include <linux/platform_device.h>
12 #include <linux/regmap.h>
13 #include <linux/thermal.h>
14 
15 #define MLXREG_FAN_MAX_TACHO		14
16 #define MLXREG_FAN_MAX_PWM		4
17 #define MLXREG_FAN_PWM_NOT_CONNECTED	0xff
18 #define MLXREG_FAN_MAX_STATE		10
19 #define MLXREG_FAN_MIN_DUTY		51	/* 20% */
20 #define MLXREG_FAN_MAX_DUTY		255	/* 100% */
21 #define MLXREG_FAN_SPEED_MIN_LEVEL		2	/* 20 percent */
22 #define MLXREG_FAN_TACHO_SAMPLES_PER_PULSE_DEF	44
23 #define MLXREG_FAN_TACHO_DIV_MIN		283
24 #define MLXREG_FAN_TACHO_DIV_DEF		(MLXREG_FAN_TACHO_DIV_MIN * 4)
25 #define MLXREG_FAN_TACHO_DIV_SCALE_MAX	64
26 /*
27  * FAN datasheet defines the formula for RPM calculations as RPM = 15/t-high.
28  * The logic in a programmable device measures the time t-high by sampling the
29  * tachometer every t-sample (with the default value 11.32 uS) and increment
30  * a counter (N) as long as the pulse has not change:
31  * RPM = 15 / (t-sample * (K + Regval)), where:
32  * Regval: is the value read from the programmable device register;
33  *  - 0xff - represents tachometer fault;
34  *  - 0xfe - represents tachometer minimum value , which is 4444 RPM;
35  *  - 0x00 - represents tachometer maximum value , which is 300000 RPM;
36  * K: is 44 and it represents the minimum allowed samples per pulse;
37  * N: is equal K + Regval;
38  * In order to calculate RPM from the register value the following formula is
39  * used: RPM = 15 / ((Regval + K) * 11.32) * 10^(-6)), which in  the
40  * default case is modified to:
41  * RPM = 15000000 * 100 / ((Regval + 44) * 1132);
42  * - for Regval 0x00, RPM will be 15000000 * 100 / (44 * 1132) = 30115;
43  * - for Regval 0xfe, RPM will be 15000000 * 100 / ((254 + 44) * 1132) = 4446;
44  * In common case the formula is modified to:
45  * RPM = 15000000 * 100 / ((Regval + samples) * divider).
46  */
47 #define MLXREG_FAN_GET_RPM(rval, d, s)	(DIV_ROUND_CLOSEST(15000000 * 100, \
48 					 ((rval) + (s)) * (d)))
49 #define MLXREG_FAN_GET_FAULT(val, mask) ((val) == (mask))
50 #define MLXREG_FAN_PWM_DUTY2STATE(duty)	(DIV_ROUND_CLOSEST((duty) *	\
51 					 MLXREG_FAN_MAX_STATE,		\
52 					 MLXREG_FAN_MAX_DUTY))
53 #define MLXREG_FAN_PWM_STATE2DUTY(stat)	(DIV_ROUND_CLOSEST((stat) *	\
54 					 MLXREG_FAN_MAX_DUTY,		\
55 					 MLXREG_FAN_MAX_STATE))
56 
57 struct mlxreg_fan;
58 
59 /*
60  * struct mlxreg_fan_tacho - tachometer data (internal use):
61  *
62  * @connected: indicates if tachometer is connected;
63  * @reg: register offset;
64  * @mask: fault mask;
65  * @prsnt: present register offset;
66  */
67 struct mlxreg_fan_tacho {
68 	bool connected;
69 	u32 reg;
70 	u32 mask;
71 	u32 prsnt;
72 };
73 
74 /*
75  * struct mlxreg_fan_pwm - PWM data (internal use):
76  *
77  * @fan: private data;
78  * @connected: indicates if PWM is connected;
79  * @reg: register offset;
80  * @cooling: cooling device levels;
81  * @last_hwmon_state: last cooling state set by hwmon subsystem;
82  * @last_thermal_state: last cooling state set by thermal subsystem;
83  * @cdev: cooling device;
84  */
85 struct mlxreg_fan_pwm {
86 	struct mlxreg_fan *fan;
87 	bool connected;
88 	u32 reg;
89 	unsigned long last_hwmon_state;
90 	unsigned long last_thermal_state;
91 	struct thermal_cooling_device *cdev;
92 };
93 
94 /*
95  * struct mlxreg_fan - private data (internal use):
96  *
97  * @dev: basic device;
98  * @regmap: register map of parent device;
99  * @tacho: tachometer data;
100  * @pwm: PWM data;
101  * @tachos_per_drwr - number of tachometers per drawer;
102  * @samples: minimum allowed samples per pulse;
103  * @divider: divider value for tachometer RPM calculation;
104  */
105 struct mlxreg_fan {
106 	struct device *dev;
107 	void *regmap;
108 	struct mlxreg_core_platform_data *pdata;
109 	struct mlxreg_fan_tacho tacho[MLXREG_FAN_MAX_TACHO];
110 	struct mlxreg_fan_pwm pwm[MLXREG_FAN_MAX_PWM];
111 	int tachos_per_drwr;
112 	int samples;
113 	int divider;
114 };
115 
116 static int mlxreg_fan_set_cur_state(struct thermal_cooling_device *cdev,
117 				    unsigned long state);
118 
119 static int
mlxreg_fan_read(struct device * dev,enum hwmon_sensor_types type,u32 attr,int channel,long * val)120 mlxreg_fan_read(struct device *dev, enum hwmon_sensor_types type, u32 attr,
121 		int channel, long *val)
122 {
123 	struct mlxreg_fan *fan = dev_get_drvdata(dev);
124 	struct mlxreg_fan_tacho *tacho;
125 	struct mlxreg_fan_pwm *pwm;
126 	u32 regval;
127 	int err;
128 
129 	switch (type) {
130 	case hwmon_fan:
131 		tacho = &fan->tacho[channel];
132 		switch (attr) {
133 		case hwmon_fan_input:
134 			/*
135 			 * Check FAN presence: FAN related bit in presence register is one,
136 			 * if FAN is physically connected, zero - otherwise.
137 			 */
138 			if (tacho->prsnt && fan->tachos_per_drwr) {
139 				err = regmap_read(fan->regmap, tacho->prsnt, &regval);
140 				if (err)
141 					return err;
142 
143 				/*
144 				 * Map channel to presence bit - drawer can be equipped with
145 				 * one or few FANs, while presence is indicated per drawer.
146 				 */
147 				if (BIT(channel / fan->tachos_per_drwr) & regval) {
148 					/* FAN is not connected - return zero for FAN speed. */
149 					*val = 0;
150 					return 0;
151 				}
152 			}
153 
154 			err = regmap_read(fan->regmap, tacho->reg, &regval);
155 			if (err)
156 				return err;
157 
158 			*val = MLXREG_FAN_GET_RPM(regval, fan->divider,
159 						  fan->samples);
160 			break;
161 
162 		case hwmon_fan_fault:
163 			err = regmap_read(fan->regmap, tacho->reg, &regval);
164 			if (err)
165 				return err;
166 
167 			*val = MLXREG_FAN_GET_FAULT(regval, tacho->mask);
168 			break;
169 
170 		default:
171 			return -EOPNOTSUPP;
172 		}
173 		break;
174 
175 	case hwmon_pwm:
176 		pwm = &fan->pwm[channel];
177 		switch (attr) {
178 		case hwmon_pwm_input:
179 			err = regmap_read(fan->regmap, pwm->reg, &regval);
180 			if (err)
181 				return err;
182 
183 			*val = regval;
184 			break;
185 
186 		default:
187 			return -EOPNOTSUPP;
188 		}
189 		break;
190 
191 	default:
192 		return -EOPNOTSUPP;
193 	}
194 
195 	return 0;
196 }
197 
198 static int
mlxreg_fan_write(struct device * dev,enum hwmon_sensor_types type,u32 attr,int channel,long val)199 mlxreg_fan_write(struct device *dev, enum hwmon_sensor_types type, u32 attr,
200 		 int channel, long val)
201 {
202 	struct mlxreg_fan *fan = dev_get_drvdata(dev);
203 	struct mlxreg_fan_pwm *pwm;
204 
205 	switch (type) {
206 	case hwmon_pwm:
207 		switch (attr) {
208 		case hwmon_pwm_input:
209 			if (val < MLXREG_FAN_MIN_DUTY ||
210 			    val > MLXREG_FAN_MAX_DUTY)
211 				return -EINVAL;
212 			pwm = &fan->pwm[channel];
213 			/* If thermal is configured - handle PWM limit setting. */
214 			if (IS_REACHABLE(CONFIG_THERMAL)) {
215 				pwm->last_hwmon_state = MLXREG_FAN_PWM_DUTY2STATE(val);
216 				/*
217 				 * Update PWM only in case requested state is not less than the
218 				 * last thermal state.
219 				 */
220 				if (pwm->last_hwmon_state >= pwm->last_thermal_state)
221 					return mlxreg_fan_set_cur_state(pwm->cdev,
222 									pwm->last_hwmon_state);
223 				return 0;
224 			}
225 			return regmap_write(fan->regmap, pwm->reg, val);
226 		default:
227 			return -EOPNOTSUPP;
228 		}
229 		break;
230 
231 	default:
232 		return -EOPNOTSUPP;
233 	}
234 
235 	return -EOPNOTSUPP;
236 }
237 
238 static umode_t
mlxreg_fan_is_visible(const void * data,enum hwmon_sensor_types type,u32 attr,int channel)239 mlxreg_fan_is_visible(const void *data, enum hwmon_sensor_types type, u32 attr,
240 		      int channel)
241 {
242 	switch (type) {
243 	case hwmon_fan:
244 		if (!(((struct mlxreg_fan *)data)->tacho[channel].connected))
245 			return 0;
246 
247 		switch (attr) {
248 		case hwmon_fan_input:
249 		case hwmon_fan_fault:
250 			return 0444;
251 		default:
252 			break;
253 		}
254 		break;
255 
256 	case hwmon_pwm:
257 		if (!(((struct mlxreg_fan *)data)->pwm[channel].connected))
258 			return 0;
259 
260 		switch (attr) {
261 		case hwmon_pwm_input:
262 			return 0644;
263 		default:
264 			break;
265 		}
266 		break;
267 
268 	default:
269 		break;
270 	}
271 
272 	return 0;
273 }
274 
275 static char *mlxreg_fan_name[] = {
276 	"mlxreg_fan",
277 	"mlxreg_fan1",
278 	"mlxreg_fan2",
279 	"mlxreg_fan3",
280 };
281 
282 static const struct hwmon_channel_info *mlxreg_fan_hwmon_info[] = {
283 	HWMON_CHANNEL_INFO(fan,
284 			   HWMON_F_INPUT | HWMON_F_FAULT,
285 			   HWMON_F_INPUT | HWMON_F_FAULT,
286 			   HWMON_F_INPUT | HWMON_F_FAULT,
287 			   HWMON_F_INPUT | HWMON_F_FAULT,
288 			   HWMON_F_INPUT | HWMON_F_FAULT,
289 			   HWMON_F_INPUT | HWMON_F_FAULT,
290 			   HWMON_F_INPUT | HWMON_F_FAULT,
291 			   HWMON_F_INPUT | HWMON_F_FAULT,
292 			   HWMON_F_INPUT | HWMON_F_FAULT,
293 			   HWMON_F_INPUT | HWMON_F_FAULT,
294 			   HWMON_F_INPUT | HWMON_F_FAULT,
295 			   HWMON_F_INPUT | HWMON_F_FAULT,
296 			   HWMON_F_INPUT | HWMON_F_FAULT,
297 			   HWMON_F_INPUT | HWMON_F_FAULT),
298 	HWMON_CHANNEL_INFO(pwm,
299 			   HWMON_PWM_INPUT,
300 			   HWMON_PWM_INPUT,
301 			   HWMON_PWM_INPUT,
302 			   HWMON_PWM_INPUT),
303 	NULL
304 };
305 
306 static const struct hwmon_ops mlxreg_fan_hwmon_hwmon_ops = {
307 	.is_visible = mlxreg_fan_is_visible,
308 	.read = mlxreg_fan_read,
309 	.write = mlxreg_fan_write,
310 };
311 
312 static const struct hwmon_chip_info mlxreg_fan_hwmon_chip_info = {
313 	.ops = &mlxreg_fan_hwmon_hwmon_ops,
314 	.info = mlxreg_fan_hwmon_info,
315 };
316 
mlxreg_fan_get_max_state(struct thermal_cooling_device * cdev,unsigned long * state)317 static int mlxreg_fan_get_max_state(struct thermal_cooling_device *cdev,
318 				    unsigned long *state)
319 {
320 	*state = MLXREG_FAN_MAX_STATE;
321 	return 0;
322 }
323 
mlxreg_fan_get_cur_state(struct thermal_cooling_device * cdev,unsigned long * state)324 static int mlxreg_fan_get_cur_state(struct thermal_cooling_device *cdev,
325 				    unsigned long *state)
326 
327 {
328 	struct mlxreg_fan_pwm *pwm = cdev->devdata;
329 	struct mlxreg_fan *fan = pwm->fan;
330 	u32 regval;
331 	int err;
332 
333 	err = regmap_read(fan->regmap, pwm->reg, &regval);
334 	if (err) {
335 		dev_err(fan->dev, "Failed to query PWM duty\n");
336 		return err;
337 	}
338 
339 	*state = MLXREG_FAN_PWM_DUTY2STATE(regval);
340 
341 	return 0;
342 }
343 
mlxreg_fan_set_cur_state(struct thermal_cooling_device * cdev,unsigned long state)344 static int mlxreg_fan_set_cur_state(struct thermal_cooling_device *cdev,
345 				    unsigned long state)
346 
347 {
348 	struct mlxreg_fan_pwm *pwm = cdev->devdata;
349 	struct mlxreg_fan *fan = pwm->fan;
350 	int err;
351 
352 	if (state > MLXREG_FAN_MAX_STATE)
353 		return -EINVAL;
354 
355 	/* Save thermal state. */
356 	pwm->last_thermal_state = state;
357 
358 	state = max_t(unsigned long, state, pwm->last_hwmon_state);
359 	err = regmap_write(fan->regmap, pwm->reg,
360 			   MLXREG_FAN_PWM_STATE2DUTY(state));
361 	if (err) {
362 		dev_err(fan->dev, "Failed to write PWM duty\n");
363 		return err;
364 	}
365 	return 0;
366 }
367 
368 static const struct thermal_cooling_device_ops mlxreg_fan_cooling_ops = {
369 	.get_max_state	= mlxreg_fan_get_max_state,
370 	.get_cur_state	= mlxreg_fan_get_cur_state,
371 	.set_cur_state	= mlxreg_fan_set_cur_state,
372 };
373 
mlxreg_fan_connect_verify(struct mlxreg_fan * fan,struct mlxreg_core_data * data)374 static int mlxreg_fan_connect_verify(struct mlxreg_fan *fan,
375 				     struct mlxreg_core_data *data)
376 {
377 	u32 regval;
378 	int err;
379 
380 	err = regmap_read(fan->regmap, data->capability, &regval);
381 	if (err) {
382 		dev_err(fan->dev, "Failed to query capability register 0x%08x\n",
383 			data->capability);
384 		return err;
385 	}
386 
387 	return !!(regval & data->bit);
388 }
389 
mlxreg_pwm_connect_verify(struct mlxreg_fan * fan,struct mlxreg_core_data * data)390 static int mlxreg_pwm_connect_verify(struct mlxreg_fan *fan,
391 				     struct mlxreg_core_data *data)
392 {
393 	u32 regval;
394 	int err;
395 
396 	err = regmap_read(fan->regmap, data->reg, &regval);
397 	if (err) {
398 		dev_err(fan->dev, "Failed to query pwm register 0x%08x\n",
399 			data->reg);
400 		return err;
401 	}
402 
403 	return regval != MLXREG_FAN_PWM_NOT_CONNECTED;
404 }
405 
mlxreg_fan_speed_divider_get(struct mlxreg_fan * fan,struct mlxreg_core_data * data)406 static int mlxreg_fan_speed_divider_get(struct mlxreg_fan *fan,
407 					struct mlxreg_core_data *data)
408 {
409 	u32 regval;
410 	int err;
411 
412 	err = regmap_read(fan->regmap, data->capability, &regval);
413 	if (err) {
414 		dev_err(fan->dev, "Failed to query capability register 0x%08x\n",
415 			data->capability);
416 		return err;
417 	}
418 
419 	/*
420 	 * Set divider value according to the capability register, in case it
421 	 * contains valid value. Otherwise use default value. The purpose of
422 	 * this validation is to protect against the old hardware, in which
423 	 * this register can return zero.
424 	 */
425 	if (regval > 0 && regval <= MLXREG_FAN_TACHO_DIV_SCALE_MAX)
426 		fan->divider = regval * MLXREG_FAN_TACHO_DIV_MIN;
427 
428 	return 0;
429 }
430 
mlxreg_fan_config(struct mlxreg_fan * fan,struct mlxreg_core_platform_data * pdata)431 static int mlxreg_fan_config(struct mlxreg_fan *fan,
432 			     struct mlxreg_core_platform_data *pdata)
433 {
434 	int tacho_num = 0, tacho_avail = 0, pwm_num = 0, i;
435 	struct mlxreg_core_data *data = pdata->data;
436 	bool configured = false;
437 	int err;
438 
439 	fan->samples = MLXREG_FAN_TACHO_SAMPLES_PER_PULSE_DEF;
440 	fan->divider = MLXREG_FAN_TACHO_DIV_DEF;
441 	for (i = 0; i < pdata->counter; i++, data++) {
442 		if (strnstr(data->label, "tacho", sizeof(data->label))) {
443 			if (tacho_num == MLXREG_FAN_MAX_TACHO) {
444 				dev_err(fan->dev, "too many tacho entries: %s\n",
445 					data->label);
446 				return -EINVAL;
447 			}
448 
449 			if (data->capability) {
450 				err = mlxreg_fan_connect_verify(fan, data);
451 				if (err < 0)
452 					return err;
453 				else if (!err) {
454 					tacho_num++;
455 					continue;
456 				}
457 			}
458 
459 			fan->tacho[tacho_num].reg = data->reg;
460 			fan->tacho[tacho_num].mask = data->mask;
461 			fan->tacho[tacho_num].prsnt = data->reg_prsnt;
462 			fan->tacho[tacho_num++].connected = true;
463 			tacho_avail++;
464 		} else if (strnstr(data->label, "pwm", sizeof(data->label))) {
465 			if (pwm_num == MLXREG_FAN_MAX_TACHO) {
466 				dev_err(fan->dev, "too many pwm entries: %s\n",
467 					data->label);
468 				return -EINVAL;
469 			}
470 
471 			/* Validate if more then one PWM is connected. */
472 			if (pwm_num) {
473 				err = mlxreg_pwm_connect_verify(fan, data);
474 				if (err < 0)
475 					return err;
476 				else if (!err)
477 					continue;
478 			}
479 
480 			fan->pwm[pwm_num].reg = data->reg;
481 			fan->pwm[pwm_num].connected = true;
482 			pwm_num++;
483 		} else if (strnstr(data->label, "conf", sizeof(data->label))) {
484 			if (configured) {
485 				dev_err(fan->dev, "duplicate conf entry: %s\n",
486 					data->label);
487 				return -EINVAL;
488 			}
489 			/* Validate that conf parameters are not zeros. */
490 			if (!data->mask && !data->bit && !data->capability) {
491 				dev_err(fan->dev, "invalid conf entry params: %s\n",
492 					data->label);
493 				return -EINVAL;
494 			}
495 			if (data->capability) {
496 				err = mlxreg_fan_speed_divider_get(fan, data);
497 				if (err)
498 					return err;
499 			} else {
500 				if (data->mask)
501 					fan->samples = data->mask;
502 				if (data->bit)
503 					fan->divider = data->bit;
504 			}
505 			configured = true;
506 		} else {
507 			dev_err(fan->dev, "invalid label: %s\n", data->label);
508 			return -EINVAL;
509 		}
510 	}
511 
512 	if (pdata->capability) {
513 		int drwr_avail;
514 		u32 regval;
515 
516 		/* Obtain the number of FAN drawers, supported by system. */
517 		err = regmap_read(fan->regmap, pdata->capability, &regval);
518 		if (err) {
519 			dev_err(fan->dev, "Failed to query capability register 0x%08x\n",
520 				pdata->capability);
521 			return err;
522 		}
523 
524 		drwr_avail = hweight32(regval);
525 		if (!tacho_avail || !drwr_avail || tacho_avail < drwr_avail) {
526 			dev_err(fan->dev, "Configuration is invalid: drawers num %d tachos num %d\n",
527 				drwr_avail, tacho_avail);
528 			return -EINVAL;
529 		}
530 
531 		/* Set the number of tachometers per one drawer. */
532 		fan->tachos_per_drwr = tacho_avail / drwr_avail;
533 	}
534 
535 	return 0;
536 }
537 
mlxreg_fan_cooling_config(struct device * dev,struct mlxreg_fan * fan)538 static int mlxreg_fan_cooling_config(struct device *dev, struct mlxreg_fan *fan)
539 {
540 	int i;
541 
542 	for (i = 0; i < MLXREG_FAN_MAX_PWM; i++) {
543 		struct mlxreg_fan_pwm *pwm = &fan->pwm[i];
544 
545 		if (!pwm->connected)
546 			continue;
547 		pwm->fan = fan;
548 		pwm->cdev = devm_thermal_of_cooling_device_register(dev, NULL, mlxreg_fan_name[i],
549 								    pwm, &mlxreg_fan_cooling_ops);
550 		if (IS_ERR(pwm->cdev)) {
551 			dev_err(dev, "Failed to register cooling device\n");
552 			return PTR_ERR(pwm->cdev);
553 		}
554 
555 		/* Set minimal PWM speed. */
556 		pwm->last_hwmon_state = MLXREG_FAN_PWM_DUTY2STATE(MLXREG_FAN_MIN_DUTY);
557 	}
558 
559 	return 0;
560 }
561 
mlxreg_fan_probe(struct platform_device * pdev)562 static int mlxreg_fan_probe(struct platform_device *pdev)
563 {
564 	struct mlxreg_core_platform_data *pdata;
565 	struct device *dev = &pdev->dev;
566 	struct mlxreg_fan *fan;
567 	struct device *hwm;
568 	int err;
569 
570 	pdata = dev_get_platdata(dev);
571 	if (!pdata) {
572 		dev_err(dev, "Failed to get platform data.\n");
573 		return -EINVAL;
574 	}
575 
576 	fan = devm_kzalloc(dev, sizeof(*fan), GFP_KERNEL);
577 	if (!fan)
578 		return -ENOMEM;
579 
580 	fan->dev = dev;
581 	fan->regmap = pdata->regmap;
582 
583 	err = mlxreg_fan_config(fan, pdata);
584 	if (err)
585 		return err;
586 
587 	hwm = devm_hwmon_device_register_with_info(dev, "mlxreg_fan",
588 						   fan,
589 						   &mlxreg_fan_hwmon_chip_info,
590 						   NULL);
591 	if (IS_ERR(hwm)) {
592 		dev_err(dev, "Failed to register hwmon device\n");
593 		return PTR_ERR(hwm);
594 	}
595 
596 	if (IS_REACHABLE(CONFIG_THERMAL))
597 		err = mlxreg_fan_cooling_config(dev, fan);
598 
599 	return err;
600 }
601 
602 static struct platform_driver mlxreg_fan_driver = {
603 	.driver = {
604 	    .name = "mlxreg-fan",
605 	},
606 	.probe = mlxreg_fan_probe,
607 };
608 
609 module_platform_driver(mlxreg_fan_driver);
610 
611 MODULE_AUTHOR("Vadim Pasternak <vadimp@mellanox.com>");
612 MODULE_DESCRIPTION("Mellanox FAN driver");
613 MODULE_LICENSE("GPL");
614 MODULE_ALIAS("platform:mlxreg-fan");
615